Milling machine



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Filed Jan. 11, 1935 12 Sheets-Sheet 9 m: 3 Eu 7 mi 5 & $5 at N: v Q \R\ %W\ k a? g NE 9: r 3 SM .n 6 hi INVENTOEJ Jan, 14, 193. H. o. FLETCHER MILLING MACHINE Filed Jan. 11, 1935 12 Sheets-Sheet l0 //v VEN TO Jan, M, 11.9%. H. o. FLETCHER MILLING MACHINE Fil ed Jan. 11, 1955' 1.2 Sheets-Sheet 11 BE R H. o. FLETCHER MILLING MACHINE Filed Jan 11, 1935 12 Sheets-Sheet 12 Qww i a tented Jan. 14, 1936 UNITED STATES MILLING MACHINE Henry 0. Fletcher, Manchester, N. H.

Application January 11, 1935, Serial No. 1,378 20 Claims. (01. 90-151) My invention relates to milling machines, and

especially to the automatic type, for performing operations on machine parts where a great number of similar parts are required, many of the important movements being accomplished by hydraulic means.

Some of the objects of my invention are to simplify the construction and provide positive movements.

10 In all milling machines there is a great tendency to force the cutter from its intended path of operation by the resistance of the work causing chatter and imperfect work, and excessive hydraulic pressure, when employed for the purpose 15 of overcoming the difficulty is necessary. In the present invention I employ positive means for holding the cutter to its true path of operation thus overcoming this tendency.

Means is also provided in the present invention 20 for preventing the advance of the cutter previous to the completion of the rotary movement of the work holder. This is accomplished by closing and opening a valve in the pipe for supplying fluid to the cutter advancing motor by means of cams carried bythe work holder.

Provision is also made for conducting fluid from a stationary source to a hydraulic motor carried by a reciprocating part without the use of telescoping, or slip joints in the conductors. This is 30 accomplished by passing the fluid through passages formed in the piston, and. piston rod, of the stationary motor which operates the reciprocating part.

Another improvement consists of assisting to 35 bring the work holder to a gradual stop during the latter part of its rotation by closing a valve in the supply line leading to the indexing motor.

Still another improvement in the introduction of a novel roller bearing on which the heavy reciprocating parts are carried thus greatly reducing friction and the power necessary to move the parts.

Other objects will be made evident by the description and claims.

As the herein described improvements are so distributed and related to the entire working of a milling machine it has been deemed necessary to represent a complete milling machine in the drawings.

50 Fig. 1 is a side elevation of one embodiment of the invention, Fig. 2 is a plan view, and Fig. 3 is an end view looking from the right of Fig. 1.

Fig. 4 is a diagram of the hydraulic connections. Fig. 5 is a sectional view of the main valve, and 55 Figs. 6 and 7 are sectional views of the same taken on lines 6 and I of Fig. 5, parts being broken away to more fully reveal the operations.

Fig. 8 is a side view of the device for automatically opening and closing the valve supplying fluid to the turret indexing motor, showing the valve partialy closed, and Fig. 9 is an end view of the same. Figs. 10 and 11 are views respectively similar to Figs. 8 and 9 showing the valve open.

Figs. 12 and 13 are side elevations of the device for engaging and disengaging the indexing rack, and looking it in engaged and disengaged positions.

Fig. 1a is a front view, and Figs. 15 and 16 are side views of the toggle movement to prevent chattering. Fig. 17 is a plan view of a load and fire mechanism used for operating the auxiliary valve.

Fig. 18 is a side elevation of an embodiment employing a reciprocating work holder, Fig. 19 is a plan view, and Fig. 20 is an end elevation of the same looking from the right of Fig. 18.

Fig. 21 is a diagram of the hydraulic connections used for operating the motors, and Fig. 22 is a diagram of the piping system to control the movements of the work holder.

Fig. 23 is a plan; view of the auxiliary reversing valve and Fig. 24. is a sectional elevation of the same,

Fig. 25 is a side elevation of another locking device together with the device for engaging the turret indexing motor.

Fig. 26 is a plan view of the load and fire device for operating the main reversing valve.

Fig. 27 is a modification of the piping system shown in Fig. 4, and Fig. 28 represents a piping system auxiliary to that shown in Fig. 27, and Fig. 29 is a plan view of the reversing valve shown in Fig. 28.

Fig. 30 is a front elevation showing a method of operating the toggle for holding the cutter with rigidity during its operation on the work, and Fig. 31 is a. side sectional view taken on line 3 I3l of Fig. 30. Figs. 32 and 33 are views similar to Fig. 31 showing the parts in various position of operation. Fig. 34 is a plan View of Fig. 30.

Figs. 35 and 36 are side views showing another method of operating the toggle, and Figs. 37 and 38 are side views showing still another method of operating the toggle.

Figs. 39 to 42 are planviews of a modified mechanism for operating the main valve showing the parts in various positions of operation.

Fig. 43 is a plan view of the work holder showing the method of clamping the work in position and also the manner of locking the work holder during the operation by the cutter. Figs. 44 and are side views showing the manner of operating the toggles illustrated in Figs. 3'7 and 38.

Fig. 46 is a plan View of piston II), of the main valve 1, and Figs. 47 and 48 are sectional views of the same, the section being taken on lines 41 and 48, respectively, of Fig. 46.

Referring to Figs. 1 to 3 the base supports table 2, upon which most of the mechanism is mounted, and the pump 3, mounted within base I supplies fluid under pressure from tank 4 through pipe lines to the various hydraulic motors.

The pipe 6 through various branches, supplies fluid under pressure to the various motors and the fiuid is controlled by valves as will be hereafter explained.

The carriage I5 is reciprocated by hydraulic motor I3, being guided in ways formed in table 2, and bar I8 is adjustably fastened to carriage I5, as shown. The cutter carrying slide 3|, slidably mounted on carriage I5, is raised and lowered by hydraulic motor 36 rigidly mounted on carriage I5. Cutter 39 is adjustably mounted on slide 3|.

Fluid is supplied to main valve 1 through pipe 6a and port 9, (see Figs. 4 and 5). When piston I9 is in its right hand position, and segment 46 formed on piston I6 is in the position shown in Fig. 6, fluid flows through pipe II and valve I2, to the right hand end of cylinder I3 to advance piston I4 and carriage I5. The valve I2, two arm lever I6, check valve I1 and slide bar I8 serve to control the movements of carriage I5, but constitute no part of the present invention.

The turret 26 rotates in a bearing rigidly mounted on table 2 in the usual manner, and is rotated by means of the action of piston 66 of hydraulic motor 18 which will hereinafter be explained.

The valve I9, interposed in pipe II, is automatically opened and closed by rod 20. Pinion 2|, fast on rod 29, meshes with rack 22, which slides in bearing 23. Roll 24 is pivoted at 25 in rack 22, and is held against turret 26 by means of torsional spring 21 fastened at one end to collar 28, fast on rod 20, and at the other end to bearing 23. The cams 29, project from the periphery of turret 26, to operate rack 22, and rod 2|] for opening and closing valve I9.

When turret 26 starts to rotate cam 29 recedes from roll 24, and spring 21 rotates rod 20 to close valve I9, and as turret 26 is completing its rotation another cam 29 operates rack 22, pinion 2| and rod 20 to open valve I9. Thus it will be seen that no fluid can flow to cylinder I3 to advance carriage I5 until turret 26 has completed its rotation.

The pipe 256, containing check valve 251, bypasses valve I9 to allow free flow of the exhaust from the right hand end of cylinder I3 in the direction of the arrow when valve I9 is closed.

This precludes any trouble that may be caused by the advance of carriage I5, and cutter 36, before the completion of the rotation of turret 26.

Cutter 33 is driven by an electric motor, mounted on carriage I 5, through gearing, not shown, as it forms no part of my invention.

The slide 3| carrying cutter 39 is slidably mounted on the carriage I5 for raising the cutter to clear the work and lowering it to operative position.

Pipe 32 leads from pipe II to locking motor 33 to lock turret 26 firmly in position during the operation of the cutter upon the work.

Pipe 34 leads from valve 1, as shown, to the left hand end of cylinder I3 to propel piston I4 and carriage I5 to the right.

Pipe 8 leads from pipe 34 to locking motor 33, as shown to unlock turret 26 which will hereafter be explained.

Pipe 35 leads from valve 1, at port 35a, to the upper end of cylinder 36 to propel piston 31 and slide 3| downward; and pipe 38 leads from valve 1. at port 38a, to the lower end of cylinder 36 to raise slide 3| and cutter 33.

Telescoping connections are interposed in pipes 35 and 38 as shown to allow movement of carriage I5 and keep the pressure intact, but form no part of my invention.

The piston rod 39, integral with piston I0, extends through bearing 49; and the arm 4|, fast on rod 39, extends into the path of blocks 42 and 43, adjustably clamped to slide 3| by means of T slot 44. When slide 3| raises, the extended arm 43a, of block 43, engages arm 4| turning rod 39 L anti-clockwise as viewed in Fig. 7. When slide 3| lowers, block 42 engages arm 4| to turn rod 39 clockwise as shown in Fig. 6.

It will be seen by the foregoing, that the blocks,

or dogs, 42 and 43 rotate piston I0 in valve cylinder 1. The segment 46 is formed integral with piston I6 and normally covers the port opening Ila, leading to pipe II, so that no fluid will flow through pipe I I until dog 42 has engaged arm 4| to rotate segment 46 into the position shown in Y Fig. 6, uncovering port I Ia. Thus it will be seen that carriage I5 will not advance until slide 3| has lowered. In the same manner segment 41 formed on piston I0 will cover port 34a, after piston I0 is propelled to the left, (see Fig. 4) until dog 43 has rotated piston III to the position shown in Fig. '1, thus preventing the return of carriage I5 previous to the raising of slide 3| and cutter 30.

The pipe 49 connects supply pipe 6 with the auxiliary valve 48 to supply pressure fluid to valve 48 (see Figs. 4 and 17).

The piston 50 oscillates in valve 48, and is integral with rod 5| which extends through cylinder, or tube, 52 and bearing 53. The collar 6| is securely fastened to rod 5|, and is normally held in alignment with the inwardly projecting ledge 54, formed in tube 52. The washers 51 and 58 are loosely mounted on rod 5|, and are held against ledge 54 by means of springs 55 and 56, respectively, which are held under compression by collars59 and 6|], respectively fast in the tube 52. The latch 62 is pivotally mounted at 63 in bearing 53, and is normally held in latched engagement with groove 64 or groove 65 formed in rod 5| by a spring not shown. The collar 12 is adjustably mounted on tube 52, and has the projecting arm 12a which extends into the path of dogs 66 and 61 adjustably mounted on slide bar I8 which partakes of the reciprocating movement of carriage I5. The collar 68 is also adjustably mounted on tube 52 and carries the extending finger 69 which slides in a guide formed in the top of bearing 53.

The cam surfaces 10 and 1| are formed on the side finger 69 and are adapted to engage latch 62 to force it out of engagement with groove 64.

When dog 61, by reason of the movement of carriage I5 and bar I8, engages collar 12, to force tube 52 to the right collar 69 compresses spring 56, as collar 6| prevents movement of washer 58, the rod 5| being held from movement by the engagement of latch 62 with groove 64. This compression takes place until cam 1| disengages latch 62 from groove 64, when spring 56 forces rod 5| and piston 56 to the right, reversing valve 48. When dog 66 engages collar 12, to

force tube52 to the left, spring 55 is compressed, the latch 82 holding rod 5| from movement by reason of engagementwith groove65, until disengaged by-cam 78, when piston 50 is forced to the left by the action of spring 55.

Itwill be seen that the above described device constitutes a load and fire mechanism to quickly operate valve 48.

This load and fire mechanism could be applied to valve 1 and rod 39, but as the weight of the parts is such as to cause considerable inertia, a very powerful spring would be necessary.

The pipe connecting the chamber at either end of valve 48 serves to allow any air, or other fluid to pass freely from one chamber to the other to prevent any compression in eitherchamber during the action of piston 50.

Exhaust passes from valve 1 to tank 4 through pipe 16, and exhaust from valve 48 through pipe 11.

When piston is in the position shown in Fig. 17 fluid flows in at port 49a and out through pipe 13 to the right hand end of valve 1 to force piston II) to the left thus raising slide 3| which a movement uncovers the port to pipe 34 to return carriage I5, and fluid also flows through pipe 8 to operate locking motor 33 to unlock turret 26. When piston 58 is in its right hand position fluid flows through pipe 5 to the left hand end of valve 1 to force piston ID to its right hand position uncovering the port to pipe 35 supplying fluid to the upper end of cylinder 36 to lower piston 31 and slide 3|, which lowering movement uncovers the port to pipe H to advance carriage l5 and through pipe 32 to lock turret 26.

As has been explained fluid pressure flows to locking motor 33 through pipe 8 to force piston 238 outward and withdraw bolt 236 out of recess 23! formed in turret 26 to allow free movement of turret 26, and fluid pressure flows through pipe 32 to motor 33 to force bolt 236 into recess 23'! thus locking turret 26 firmly in position during the cutting operation.

After bolt 236 has been removed from recess 231, piston 238 continues its movement to connect supply pipe 611 with pipe 98 for supplying fluid to right hand end of motor 18 to index turret 26. See Figs. 4 and 43.

As bolt 236 is forced into recess 23! pipe 6a is connected to pipe 98a for sup-plying fluid to the left hand end of motor l8 to return rack 79 to initial position.

Rack BI is reciprocated by connecting rod 233, pivotally connected at one end to rack 8|, and at the other end to the lower end of lever 239, fulcrumed at 23| in bracket 232. The upper end of lever 23!] is engaged by piston rod 234, formed integral with piston 238 of locking motor 33. Collar 228, fast on rod 234, engages pins 239, fast in lever 230, to rock lever 238 clockwise as rod 284 moves to the right, (see Fig. 3) and collar 228, fast on rod 234 engages pins 239 to rock lever 230 anticlockwise as rod 2234 moved to the left.

It will be seen that, as piston 238 reciprocates, lever 238 will reciprocate rack 8|, which rotates segment82 by the engagement of tooth 83 with space 84 formed in segment 82. See Figs. 12 and 13.

Segment 82 encircles the circular part of rack 19, a portion being cut away so that the end surfaces of segment 82 engages either side of the extended part of rack 19 on which the teeth 88 are cut.

The rack 79 isslidingly fitted to segment 82, and 90th a m u edinbea insem ann t @1 3".

rotationwith each other,'but to prevent segment 82 from partaking of the reciprocating movement of rack 19. The extended portion ofrack 19, on which teeth 88 are formed, is so located that the teeth 89 terminate at their lower end on a line radial with the center of the circular portion of rack 19, the teeth being at right angle to that line, so that, as rack 19 rotates, teeth 88 will mesh with gear 85, fast on the stem of turret 26, without interference. limited at each end so that the teeth 80, of rack 79, are in exact alignment with the corresponding spaces of gear85. This insures the desired movement of turret 28.

The rack 8|, which operates segment 82 to rotate rack 19 has but a single tooth 83 of coarse pitch which meshes with the space 84, formed in segment 82, to rotate segment 82 and rack 8| in either direction. After rack 19 has been rotated anti-clockwise, as in Fig. 12, rack 8| continues its movement to the position shown, with the top of tooth 83 in engagement with surface 82a,of segment 82, thus forming a secure lock to hold the teeth 88 in perfect mesh with gear fast on turret 26. When rack '19 has been rotated to disengage teeth 88 from gear 85, tooth 83 is positioned under surface 82b of segment 82 to lock rack 19 out of engagement during its return movement, as shown in Fig. 13. Also the above described device provides a movement of locking motor which prevents the flow of fluid to motor (8, for indexing turret 26, previous to the perfect meshing of rack 79 with gear 85; and also prevents any return movement of rack 79 until it has been completely disengaged.

Referring to Figs. 4 and 8 to 11 inclusive, the piston 88, of indexing motor 78, is rigidly connected to indexing rack 19, and adjustably mounted thereon is collar 81' carrying the two projecting arms 88 and 89. The supply pipe 38 extending from locking mot-or 33, to supply fluid to motor 18 for indexing turret 26 has interposed valve 9|, on the stem of which is adjustably fastened collar 92 carrying arms 93 and 98.

When rack 19 has been rotated into meshing position with gear 85 collar 87 is in the position shown in Fig. 9, With arm 88 in alignment with arm 93, so that as piston 85 advances near the end of its stroke to index turret 26, arm 88 engages arm 93 turning collar 92 to almost, but not quite, close valve 9! gradually reducing the flow of fluid to motor 18 thus decelerating the rotation of turret 26 to effect a gradual stop. When rack 79 has been rotated out of mesh withvgear 85 fluid enters the left hand end of motor 18 through pipe 99a to return piston 86, and collar 87 is in the position shown in Fig. 11 with arm 89 in alignment with arm 94, and engages arm 94 on the return movement of piston 86 to open valve 9!. The check valve 95 and pipe 98 are interposed to allow free flow of exhaust fluid previous to the opening of valve 9|.

Referring to Figs. 4, 14, 15 and 16, the piston 31 of motor 36 is connected with, and operates, slide 3| by means of piston rod 31a, and the block 91 is rigidly mounted on rod 31a.

' A small space intervenes between block 91 and slide 3| to allow a slight lost motion between these parts, piston rod 31a being slidably mounted in slide 3|. The check nuts 98 limit the upward movement of piston rod 37a relative to slide 3|, and springs 99 tend to hold slide 3| firmly against check nuts 98. The pins I28 are fast in slide 3| and serve to prevent any turning movement of blockfll.

Also the stroke of piston86 is Links I are pivotally connected at their upper ends with studs IOI, which are adjustably mounted in carriage I5, and at the opposite ends with link I02, which are in turn, pivotally mounted on slide 3|, forming toggle joints between carriage I and slide 3|. These toggle joints are partly closed as slide 3| raises and opened as slide 3| lowers. When slide 3| has lowered to the position shown in Fig. the rolls I03, loosely mounted on the middle studs I04 of the toggles, come into engagement with the lower surfaces of the angular slots I05, formed in the sides of block 91 as shown, so that the toggle cannot straighten further until block 91 travels downward with relation to slide 3|. The completion of the toggle movement takes place during the lost motion movement described above, and as block 91 moves downward the upper surfaces of slots I05 engage rolls I03 to complete, and lock, the toggle movement, thus rigidly holding slide 3| in position as shown in Fig. 16, to prevent any chatter or vibration of slide 3| and cutter 30.

As piston 31 and block 91, move upward, the lower surfaces of slots I05 engage rolls I03, to break the toggles, and thereafter the nuts 96 engage slide 3| to raise it, thus clearing the cutter from the work.

The carriage I5 rides on rolls IIB which are .supported by table 2, and the cage, or guide II9,

forms a framework to hold rolls H8 in proper alignment. R

It will be seen that cage H9 and rolls II8 travel with carriage I5, but only half the distance of the carriage, This arrangement reduces friction to a minimum.

Referring to Figs. 18 to 26 the assembly is similar in many respects to that described above, the principal difference being that I reciprocate the work support 26a, and mount the cutter support I06 rigidly on the supporting table 2a.

The cutter carrying slide 3 Ia is slidably mounted on support I06 in the same manner as slide 3| is mounted on carriage I5, and slide 3 la is raised and lowered by motor 36a mounted on support I06.

The hydraulic motor I01 is rigidly mounted on table 2a, and the reciprocating piston I I I is connected with work support 26a. The valve 1a is operated by reversing valve I08 by means of fluid flowing through pipe I 09 and H0 and valve I08 is operated by a load and fire mechanism which will hereinafter be described.

Two passages I I I1), and I I I0, are drilled in piston rod IIIa, passage |IIb= passing through its entire length of rod I I Ia and piston I I I, connecting the rear chamber I2I with pipe II2, which in turn, is connected with the upper end of locking motor I I3, for unlocking turret 26b. Passage I I I0 passes through the entire length of rod I I Ia, but not through piston I I I, being connected with chamber I22 by short passage I I Id. Pipe II4 connects passage I I I0 with the lower end of lock ing motor M3 for locking turret 26b. Pipe II5 connects the upper chamber of motor 3 with the right hand end of indexing motor II6 for indexing turret 2611, so that pressure fluid flowing into the right hand end of motor I01 will unlock turret 26b and then operate motor 'I I6 to index turret 26b.

The pipe II1 connects the lower part of motor I I3 with the left hand end of motor I I6, so that fluid entering the left hand end of motor I01 will flow to the lower end of motor II3 to first lock turret 26b, and then to return the piston I I60, of motor I I6 to original position. The check valves I I81) and I I8a will allow the exhaust to flow from port II 3a to pipe H2, or pipe II4, but prevents the flow of pressure fluid to port I I3a.

By the foregoing it will be seen that when fluid under pressure is delivered to chamber I2I, of motor I01 that it will exert a force on piston I II to urge work support 26a, to which piston rod IIIa is connected, to the left, and also will force piston I23 in looking motor I I3 downward unlocking turret 2617, after which the port leading to pipe II5 will be uncovered delivering fluid to the right hand end of mot-or II6 to index turret 26b.

When fluid is delivered to the left hand end of motor I01 pressure is exerted on piston III to urge work support 26a to the right, and also to lock turret, 26b, after which the port leading to pipe I I1 is opened for delivering fluid to the left hand end of motor 6 to return piston H611 to its original position. v

Piston I|6a is connected to circular rack 19 in the same manner as piston 86, and segment 82 and rack 8| are operated by locking motor I I3 in substantially the same manner as by locking motor 33. The circular rack 19 engages gear 85 fast on the shaft of turret 26bin the manner before illustrated to index turret 26b. Motors I I3 and I I6 are mounted on and move with work holder 26a.

The load and fire device, for operating reversing valve I00, consists of two rods 5| a and 5Ib. Rod 5Ia carries cylinder 52a in which is contained springs 55a and 56a. These springs, as will be seen, perform similar functions, respectively as springs 55 and 56 of the previous described load and fire mechanism. The rods are firmly fastened together by yoke I24, and are adapted to slide in bearings 53a and 53b. The yoke I24 has a projecting lug |24a which extends into the path of dogs 66a and 61a carried by sliding bar I8a which, in turn, is adjustably connected to work support 26a by bracket I25. The block I26 is clamped to cylinder 52a and slot I26a, in block I26, receives roll I21, carried by arm I28, fast on the stem of reversing valve I08; and sector I29, also fast on the stem of valve I08, contains recesses |29a and |29b into which latch I30 isforced by spring I56. When work support 26a travels to the left dog 66a engages lug I24a to slide rods 5Ia and SH) to the left tending to turn the stem of reversing valve I08 clockwise, but is prevented by the engagement of latch I30 with recess I291), thus compressing spring 56a. When rod 5Ib has traveled sufficiently the beveled collar I3I, adjustably mounted on rod 5Ib, en-

gages latch I30 releasing it from recess I29b and allowing the pressure of spring 56a to turn valve I08 clockwise by the action of block I26 on roll I21 thus reversing the flow of fluid in pipes I09 and I I0 and resetting valve 1a. When work support 26a travels to the right dog 61a engages lug I24a, compressing spring 55a until collar I3I a engages latch I30, to release it from recess I29a, to allow the force of spring 5511 to turn reversing valve I08 anti-clockwise, again reversing the flow of fluid in pipes I09 and IIO, and resetting valve 1a.

The pressure supply pipe I32 supplies pressure to chamber I33, of valve I08, and thus pressure fluid flows through passage I34, to chamber I35, or I36, according to the position of rotor 1811. In the position shown in Figs. 23 and 24 pressure fluid flows through passage I 34 to chamber I35 and pipe I09 to the right hand end of valve 1a to force piston I0a to the left, and when pressure fluid flows to chamber I36, and pipe III) to the left hand end of valve la, piston IIlIa is forced to the right.

When pressure fluid flows through pipe I99 to valve la the exhaust returns through pipe III) to chamber I 36, and through passage I 39 to chamber I40, from which it is delivered to tank la through exhaust pipe MI. When fluid is delivered to valve la through pipe I III the exhaust returns through pipe I99 to chamber I35 thence to tank 411 through pipe MI.

When fluid is delivered to valve Ia through pipe I42 and piston Illa is in the position shown in Fig. 21, fluid flows through pipe I63 to the lower end of motor 36a to raise piston 3M and slide 3Ia; and, as slide 3Ia, raises dog 431), adjustably clamped to slide em, engages block I44, mounted on rack I45, to force rack I 45 upward turning pinion I #36 and segment 47a, formed on piston Illa clockwise, to open the port to pipe 34a supplying fluid to the right hand end of motor I91 to retract work support 26a. When piston Illa is moved to its left hand position fluid flows through pipe I57 to the upper end of motor 36a to lower slide 3Ia. As slide 3Ia lowers dog 42a engages block M4 to lower rack M5 and turn piston Illa to move segment 261) from the port leading to pipe Ila to supply fluid to motor III'I to advance work holder 26a.

When fluid pressure is applied to motor IIlI through pipe 36a to return work holder 25a pressure is also applied to motor M6 for rotating, or indexing, turret 26b as has been described, and there is no way to regulate the speed of the return movement of work holder 26a independent of the rotary movement of turret 26b. The device illustrated in Fig. 22 accomplishes this regulation. Cylinders I56 are mounted fast on table 2a and their piston rods I 460. are fastened at their outer ends to work holders 26a. Pipe I47 is connected to the left hand end, and pipe M8 is connected to the right hand end of cylinders I 56. These two pipes are connected together, as shown, with valves M9 and I5!) intervening. The pipe I5l, containing check valve I52, Icy-passes valve Mil so that fluid may freely flow in the direction of the arrow but flow in the opposite direction is prevented. Pipe I53 by-passes valve I59, and check valve I56 permits the flow of fluid in the direction of the arrow only.

Cylinders M6 and the connecting piping system are filled with liquid under atmospheric pressure, so that pistons I460; are restricted in their movement by valves I 9 and I5 3, the contained liquid being practically non-compressible.

When pistons i lfia are urged to the right there will be a pressure set up in pipe I ls and the flow of fluid is regulated by valve I59, and when pistons M611 are urged to the left pressure is set up in pipe MI, and the flow is regulated by valve I49. Thus the movements of work holder 26a are governed in either direction independent of the rotary movement of turret 25b.

Referring to Figs. 27 to 29, the operation of auxiliary valve 880 and main valve 10 is identical to that of valves 98 and 1, respectively, as illustrated in Fig. 4, except that the longitudinal movement of valve I90 to theright delivers fluid to the right hand end of cylinder I 30 through pipe I Is for advancing carriage I5c the fluid pressure being transmitted through passage hid, in piston I40, and pipe I69 to the upper end of motor 350 to lower the slide BI; and the segments 66c and 46d formed on piston Illc serve to open ports to pipes I61! and I62, respectively, to operate locking motor 330 for locking and unlocking the turret. When piston IIIc moves to the left fluid is delivered through pipe 340 to the left hand end of cylinder I30 for returning carriage I50, and also the fluid pressure is transmitted through passage I Ie pipe I63 to the lower end of motor 360 to raise slide 3 I.

Carriage I60 and cutter carrying slide 3| are mounted in the same manner and. perform the same functions as carriage I5 and. slide 3| shown in Figs. 1 and 2.

The valve I912 is opened and closed by rod 20a which is operated by cams 29, fast on turret 26b, in a similar manner as that of valve I9. See Figs. 1 and 2. In Figs. 18 and 19 gear 20b is slidably keyed to shaft 20a, and meshes with gear 290, fast on the stem of valve I9a. As valve I9a is not in position to line with shaft 20a gears 28b and 2B0 are interposed to connect these parts for operation.

The by-pass pipe 2M, containing check valve 242, bypasses valve Illa for the purpose of allowing the exhaust fluid to flow from the left hand end of cylinder III'I when valve I9a is closed, as indicated by the arrow.

As this arrangement provides no way to control the movement of carriage I50 independently of the movement of the cutter carrying slide 3Ia, the controlling system shown in Figs. 28 and. 29 is interposed.

Cylinder IB I is securely fastened to table 2 and piston I69 is fastened to carriage I 50 by means of lug I -56. Pipe I61 leads from the left hand end of cylinder I64 to chamber I68 in reversing valve its, and pipe I70 leads from the right hand end of cylinder I64 to chamber III in valve I69. The passage I72 in the rotor of valve I69 connects chamber III with chamber I13 when in the posi-'- tion shown, and connects chambers I68 and I74 when the rotor is tuned to its reversed position. The cylinder I66 and connecting pipes are filled with a liquid at atmospheric pressure.

When pressure is applied to the left hand end of cylinder I 30 fluid will flow through passage Me and fluid flows through pipe I63 to the lower end of motor 360 to raise slide 3I, and as fluid cannot flow from chamber I68 to chamber I14 there will be no movement of carriage I5c until slide SI raises sufficiently to turn piston I90 when the gear I76, fast on rod I90, turns gear I19 fast on the stem of valve I69, reversing valve I69, and allowing fluid to flow through pipe I8I to tank I78.

When pressure is applied to the right hand end of cylinder I lie fluid will flow through pipe I69 to lower slide BI, but piston I 40 will not retract carriage I 50 until valve I 69 is again reversed by the lowering of slide 3I to allow fluid to flow from chamber I II to chamber I I3 and to tank IIB through pipe Ill. The valves I89 regulates the return movement of carriage I50.

Having reference to Figs. 30 to 34 inclusively, the cutter slide Me is raised and lowered by the hydraulic motors 36d and 36a by means of pistons 37c and 37d. Supply pipe I 85 supplies fluid under pressure, through its branches I85d and lithe to the upper ends of motors 36d and 36a, respectively, for lowering slide 3Ie. The supply pipe I66 supplies fluid under pressure to the lower end of motors I850! and I86e to raise pistons 37d and tie, respectively, thus raising slide 3Ie.

The small hydraulic motor I81 contains piston I Illa which is adjustably connected with block I 86 containing the angular cam slots I89 into the upper ends of which rolls I90, mounted on the middle joints of toggles I9I enter as slide 3Ie lowers to the position shown in Fig. 32.

The pipe I85i leads from pipe I85 to supply fluid to the lower end of motor I81 to raise piston I81a. The valve I92 interposed in pipe I81) remains closed during the downward movement of slide 3Ie, until it reaches the position shown in Fig. 32, when valve I92 is opened by the engagement of lug 3If, extending from slide 3Ie, with collar I93 mounted on rack I94, slidable in 111 3U, lowering rack I94 and rotating pinion I95 mounted on the stem of valve I92. This upward movement of piston I81a and block I88 straightens toggle I9I by the action of ham slots I89 on rolls I90, as shown in Figure 33, thus holding slide 3Ie and the cutters mounted thereon rigidly in operating position.

The pipe I86a leads from pipe I86 to the upper end of motor I81 for lowering piston I81a. Thus it will be seen that when fluid is supplied to motors 38d and 36e through pipe I85 slide 3Ie will lower until lug 3If engages collar I83, opening valve I92 to raise piston I81a and block I88 for completing the toggle movement.

When fluid enters motors 36d and 35s through pipe I86 to raise slide 3Ie fluid also enters the upper end of motor I81 to lower piston I81a and block I88, and the upper surfaces of slots I89 engage rolls I90 to break the toggle into the position shown in Figure 32 thus releasing it to allow the completion of the upward movement of slide 3Ie.

As slide 3 le nears the end of its upward movement lug 3 If engages collar I95 to close valve I92.

The motor I81 may be made to lower block I88 to straighten toggle I9I by making slots I89 to the angle shown in Figs. 4 and 14 to 16, connecting pipe I85) to the top of motor I81 and pipe I86a to the bottom of motor I81, but I have used the arrangement shown in Figs. 30 to 34 in order that rolls I90 may more readily engage slots I89.

With reference to Figs. 35 and 36 the toggle link 200 is pivotally connected at 20I to the support 202 and link 203 is pivoted at 204 to slide 3Id. The arm 205 is integral with the link 200 and is pivotally connected at its outer end with the lower end of link 208 which in turn is pivoted at its upper end and to piston 201 reciprocated by motor 208 so that when piston 201 lowers the toggle will straighten, lowering slide 3 Id to the position shown in Fig. 36 thus holding the cutter carrying slide 3Id rigidly in operating position. When piston 201 raises slide 3Id is raised again into the position shown in Fig. 35 to clear the work by the cutter.

It is to be understood, although the cutter is not shown in Figs. 14 to 16, 30 to 38, 44 and 45, that itis mounted on the slides 3|, 3Ie, 3Id, 3If, and 3Ig, in the same manner as on slides 3|, illustrated in Figs. 1, 2, 18 and 19, also that the slides 3Id, 3Ie and SIg are mounted in thesame manner and perform the same functions as slide 3| shown in Figs. 1 and 2, or in Figs. 18 and 19.

Also that pipes I85, I85, 250 and 25I are connected With the valve distributing pressure supply fluid to their respective motors in a similar manner to that heretofore described.

In Figs. 37, 38, 44 and 45 the piston 2II, or the other moving part is connected to the middle joint 209 of the toggle by means of link 2I0. When piston 2 moves to the left the toggle is broken and slide 3Id is raised, and when piston 2 II moves to the right, to the position shown in Figs. 38 and 45, the toggle is brought to straightened position and slide 3Id is lowered to operating position.

The hydraulic cylinder 252 is mounted either on carriage If, or on a stationary framework of the machine, and reciprocates piston 2 by means of fluid flowing through pipes-253 and 254 which are connected with a main distributing valve similar to valve 1 shown in Figs. 1, 2 and 5.

With reference to Figs. 39 to 42, the valve 212 may be used instead of valve 1 and performs a similar function, and the load and fire mechanism connected therewith is similar to that shown in Fig. 17 except that ledge 54a is longer than ledge 54 to allow a limited movement of rod 5Ia independent of tube 52a which will be hereinafter explained.

The operation is by dogs 66 and 61 adjustably clamped to slide bar I8 which in turn is reciprocated by carriage I5 in the same manner as shown in Figs. 1 and 2. The piston 2I3 is operated by rod 5Ia in the same manner as rod 5I operates piston 50 of valve 48.

The cutter carrying slide 3| is mounted on carriage I5 as shown in Figs. 1, 2 and 42, and pipes 9a, I Id, 34d, 35a and 38a perform the same functions respectively, as pipes 9, I I, 34, 35 and 38 of Figs. 1, 2 and 4. Pipes 16a conduct the exhaust back to the supply tank.

When dog 61 engages lug 12a, spring 58 is compressed until cam 1I disengages latch 62 from groove 64, allowing spring 56 to slide rod 5Ia and piston 2I3 to the right into the position shown in Fig. 40, with collar 2 I1, fast on piston rod 2 I8, in position to be engaged by latch 2I9 which is pivotally mounted in slide 2 I4 as shown. When piston 2 I 3 is in the position shown in Fig. 40 carriage I5 has completed its retractive movement and the port leading to pipe 35a is connected with supply port 9b thus supplying fluid to motor 36 for lowering slide 3I. As slide 3| lowers dog 42 engages arm 4 I, turning rod 39a in the same manner as illustrated in Fig. 6. The enlarged end 220, of rod 39a, is threaded into the end of the cylindrical slide 2I4 by means of a right hand thread, and as rod 39a is held from lateral movement in either direction by collars 2I5 and 2I6, fast on rod 39a, and engaging either side of stationary bearing 401), this turning movement propels slide 2 I4, and piston 2I3 to the right into the position shown in Fig. 41, with the port leading to pipe I Id open to direct fluid to motor I3 for advancing carriage Slide 2 I4 is held against rotary movement by a stationary guide not shown.

The last described movement of piston 2I3 is efiected by means of latch 2I9, pivoted in slide 2I4, engaging collar 2I1 fast on rod 2I8, the engagement being effected by spring 22 I. As slide 2 I4 moves to the right the projecting end 2I 9a of latch 2 I 9 engages the stationary cam 222 to swing latch 2I9 out of engagement with collar 2I1 to allow a free return movement to the left of collar 2I1.

When carriage I5 has sufficiently advanced dog 86 engages lug 12a, compressing spring 55 until cam releases latch 52 from groove 65, when the force of spring 55 propels rod 5Ia and piston 2I3 to the left into the position shown in Fig. 42 which uncovers the port leading to pipe 38a thus supplying fluid to the lower end of motor 36 for raising slide 3I. In this position it will be seen that latch 223, pivoted in slide 2I4. is in engagement with collar 2 I 1 to draw it to the left.

As slide 3| raises dog 43 engages arm M to turn rod 38a into the position shown in Fig. 1,

which propels slide 2 to the left opening the port leading to pipe 3412 which supplies fluid to motor l3 to retract carriage l5 as shown in Fig. 39.

As slide 2 i4 completes its movement to the left the projecting end 223a of latch 223 engages the stationary cam 224 releasing latch 223 to allow free movement of collar 2! 1 to the right as shown.

Stop 225, attached to sleeve M4, is engaged by collar 2|! at the end of its movement to the left, to prevent excess movement of piston 2l3 due to inertia, and stop 226 serves to limit the movement to the right in a similar manner.

The operation of the various embodiments will be apparent from the foregoing description. The Work 245 is clamped on the work holder 26 by means of fixtures as shown in Fig. 43. The cutter, or work holder advances, as the case may be, until the cutter has completed its operation on the work, in the case shown to mill the flat indicated at 246. The cutter is raised to clear the work which movement initiates the relative retractive movement between the cutter and work holder, and also the unlocking of the work holder; the unlocking movement operates the indexing motor for indexing the work holder, and the first stage of the indexing movement closes the valve in the pipe supplying fluid for advancing the cutter. The retractive movement of the cutter initiates the lowering movement of the cutter; the latter part of the indexing movement opens the valve in the pipe for supplying fluid to advance the cutter; and the lowering movement of the cutter initiates the advance of the cutter.

The toggles illustrated may be operated by mechanical movements without the use of hydraulic motors. I have anticipated such changes, and I am aware that there are a variety of means for operating these toggles for rigidly holding the cutters in operating position that I have not shown. Those shown will suggest this fact.

I am aware also that the improved devices herein shown may undergo many changes in construction, and that the several devices may be combined in manners different than I have herein illustrated without departing from the spirit and scope of my invention.

Having described my invention what I claim as new is set forth in the following claims:

1. In a machine tool a work holder and a cutter, means to reciprocate one of said parts in a first path with relation to each other to effect a relative advance movement for the cutting operation and to restore the reciprocating part to j initial position, a cutter carrier adapted to raise the cutter in a second path for clearing the work and to return it to operating position, means including a hydraulic motor for raising and lowering the cutter carrier, a toggle having one end secured to prevent movement with the carrier and the other end pivotally connected to the carrier, a roll mounted on the toggle at or near its central pivotal joint, a cam carried by the motor piston adapted to engage the roll during the latter part of the return movement of the carrier to force'the toggle into' straightened position and. hold it in straightened position during the operation of the cutter on the work and to break and free the toggle during the beginning of the raising movement.

2. In a machine tool a work holder and a cutter, means to move one of said parts in a first path for performing an operation on the work by the cutter, a cutter carrier adapted to raise the cutter in a second path to clear the work, a reciprocating part for raising and lowering the cutter carrier having a slight lost motion movement with relation to the carrier during the latter part of its lowering movement, a toggle secured at one end in a manner to prevent movement with the carrier and pivotally connected at the other end to the carrier, a roll mounted on the toggle at or near its central pivotal joint, a cam carried by the reciprocating part adapted to engage the roll as the toggle approaches its straightened position to straighten the toggle during said lost motion movement and to hold the toggle in a straightened position during the operation of the cutter on the work, and to break the toggle during the lost motion portion of the raising movement.

3. In a machine tool a cutter and a work sup port, means to reciprocate one of said parts in a first path to effect an operation by the cutter upon the Work, and to return said part to initial position; a cutter carrier adapted to raise the cutter in a second path to clear the work, and returning it to operating position; means, including a hydraulic motor, for raising and lowering the cutter carrier; a toggle secured at one end to preu vent movement with the cutter carrier, and at the other end to the cutter carrier; a roll mounted on the toggle at, or near its central joint; a cam, adapted to engage said roll as the toggle approaches its straightened position, to assist in straightening the toggle, and to hold the toggle in straightened position during the operation of the cutter on the work, and to break the toggle after said operation to allow free upward movement of the carrier; and means to operate said cam.

4. In a machine tool a cutter and a work support, means to reciprocate one of said parts in a first path to effect an. operation by the cutter upon the work, and to return said part to initial position; a cutter carrier adapted to raise the cutter in a second path to clear the work, and return it to operating position; means for raising and lowering the cutter carrier; a toggle secured at one end to prevent movement with the cutter carrier, and pivoted at the other end to the cutter carrier; a roll mounted on the toggle at, or near its central joint; a cam, adapted to engage said roll as the toggle approaches its straightened position, to assist in straightening the toggle, and to hold the toggle in straightened position during the operation of the cutter on the work, and to break the toggle after said operation to allow free upward movement of the carrier; and means to operate said cam.

5. In a machine tool, a work holder and. 2.

cutter, means for reciprocating one of said parts relative to the other .to perform a cutting operation upon the work and return said part to initial position, means including a hydraulic motor for rotating the Work holder, a locking device for locking the work holder in position during the cutting operation and unlocking the work holder toallow free rotation thereof, a rack adapted to be reciprocated by said motor and also adapted to be engaged to and disengage from a gear fixed to the Work holder, means operative by the locking device for simultaneously unlocking the work holder and engaging the rack with the gear and thereafter locking the rack in engaged position and supplying fluid to the motor for rotating the work holder, means operative by the locking device for simultaneously disengaging the rack and locking the work holder and thereafter supplying fluid to the motor for returning the rack to initial position.

6. In a machine tool a cutter and a work holder; means to advance one of said parts to perform an operation on the work by the cutter, and return said part to initial position; means to rotate the work holder; a plurality of work stations fixtures carried by the work holder; a plurality of cams carried by the work holder, one cam for each station; a hydraulic motor for advancing and returning said part; pipe lines for supplying fluid under pressure to said motor; a valve in the pipe line for operating the motor to advance said part; and gearing operated by said cams whereby the valve is closed at the beginning of said rotation to prevent the advance of said part, and opened as said rotation is being terminated.

7. In a machine tool, a cutter and a work holder; means to advance one of said parts relative to the other to effect a cutting operation on the work by the cutter, and return said part to initial position; means, including a hydraulic motor having a piston and piston rod, for rotating the work holder; a pipe line for supplying fluid under pressure to one end of the motor to operate the piston for rotating the work holder, and a second pipe line leading to the other end of the motor for returning the piston to initial position; a valve in the first mentioned pipe line;

lever arms adapted to open and close the valve attached thereto; and means, operative by the movement of the piston, for engaging said arms, whereby said valve is gradually closed during the latter part of the pistons indexing stroke, and opened during its return stroke; and a pipe line bypassing said valve, containing a check valve for allowing free flow of exhaust fluid during the return stroke of the motor and checking flow of supply fluid to the motor.

8. In a machine tool, a work holder; a cutter carrying carriage, adapted to be reciprocated with relation to the work holder, to effect a cutting operation upon the work and return the carriage to initial position; a slide mounted on the carriage adapted to raise the cutter for clearing the work after the operation is completed and again lowering it to operative position; a first hydraulic motor mounted on the carriage for raising and lowering the slide; a second hydraulic motor, comprising a stationary cylinder, a piston and a piston rod adapted to reciprocate within the cylinder, the rod having connection to said carriage, and a passage through the piston and rod having pipe connection to the upper end of the first motor whereby fluid pressure introduced into the stationary cylinder for advancing the carriage will also communicate with first motor to lower the slide; means to prevent the advance of the carriage previous to the lowering of the slide; and means, operative by the lowering movement of the slide for rendering inoperative said preventing means.

9. In a machine tool, a work holder; a reciprocating carriage adapted to be reciprocated with relation to the work holder; a cutter carrying H slide mounted on the carriage for raising the cutter to clear the work after the operation upon the work is completed and again lowering the cutter to operative position; a first hydraulic motor, comprising a stationary cylinder, a piston and piston rod, the piston rod having connection with said carriage, for reciprocating the carriage; a second hydraulic motor mounted on the carriage for raising and lowering the slide; passages formed in the piston and rod of the first motor, having pipe connections with the second motor,

rocating carriage adapted to reciprocate with relation to the work holder; a cutter carrying slide mounted on the carriage for raising the cutter to clear the work after the operation upon the work is completed and again lowering the cutter to operative position; a first hydraulic motor, comprising a stationary cylinder, a piston and piston rod, the piston rod having connection with said carriage, for reciprocating the carriage; a second hydraulic motor mounted on the carriage for raising and lowering the slide; passages formed in the piston and rod of the first motor, having pipe connections with the second motor, whereby fluid pressure introduced into the first motor for advancing the carriage will also communicate with the second motor to lower the slide, and fluid pressure introduced into the first motor for retracting the carriage will also communicate with the second motor to raise the slide; means to prevent the advance of the carriage previous to the lowering of the slide and means to prevent the return of the carriage previous to the raising of the slide; means operative by the lowering movement of the slide, to free the carriage for advance movement, and means, operative by the raising movement of the slide to free the carriage allowing return movement thereof.

11. In a milling machine, a rotatable work holding turret, and a cutter; means to reciprocate one of said parts to provide an advance movement for performing a cutting operation on the work by the cutter and restore the parts to relative initial position; a first hydraulic motor for reciprocating the reciprocating part; a cutter carrying slide adapted to move the cutter in a second path for retracting the cutter from the work after the operation is completed, and restoring the cutter to operating position; a toggle pivotally connected at one end to a framework of the machine, and at the other end to the slide, so that the toggle will fold as the cutter retracts from the work and straighten as the cutter is restored to operating position; a second hydraulic motor for operating the slide and the toggle; means, including a third hydraulic motor, for rotating the turret; a locking device for locking the turret and'holding it in locked position during the operation by the cutter, and unlocking it to allow rotation thereof; a fourth hydraulic motor for operating the locking device; a piping system to distribute fluid under pressure to the motors; a valve in the pipe line leading to the first motor for advancing the reciprocating part, adapted to be closed at the beginning of the turret rotation, and opened as the turret completes its rotation; means operative by the ad Vance movement of the reciprocating part to operate the second motor for retracting the slide in the second path and folding the toggle; means operative by the retracting movement of the slide for operating the first motor for returning the reciprocating part, the fourth motor for unlocking the turret, and the third motor for ro- 

